The present invention is related to the field of Microelectromechanical Systems (MEMS). More specifically, the present invention is related to integration of film bulk acoustic resonators (FBAR) filters for different frequency bands.
Radio frequency (RF) front-end passives, such as transceivers and receivers are increasingly needed for wireless communication. These front-end passives include front-end filters. RF front-end filters consisting of FBAR have been found to have a number of advantages over other technologies, such as surface acoustic wave (SAW) devices and ceramic filters, particularly at relatively high frequencies.
The thickness of the film stack of a FBAR filter is generally governed by the half wavelength of the frequency band of the FBAR filter. For example, the thickness of the film stack of a FBAR filter for the 1900 MHz frequency band is about 1.8 μm, whereas the thickness of the film stack of a FBAR filter for the 950 MHz frequency band is about 3.6 μm.